J Thorac Cardiovasc Surg 1998;115:961
© 1998 Mosby, Inc.
Should the anticalcification effect of epoxy compound in vascular bioprostheses be judged after implantation in mongrel dogs?
Yukio Ichikawa, MD, PhD,
Yasuharu Noishiki, MD, PhD
Reply to the Editor:
The comments by Dr. Goto were difficult for us to understand. He noted that there was mild-to-moderate calcification of glutaraldehyde-treated porcine aortic cusps implanted in the pulmonary circulation of dogs, whereas no calcific changes were observed in glutaraldehyde-treated valved conduits in the systemic circulation of dogs. However, he provides no detailed explanation of what this means. He also noted that the dog is not generally considered to be a useful model for the study of accelerated calcification. This sentence was quoted directly from the original article of Dr. Shemin.
1 The point of our article was the evaluation of a trileaflet bioprosthetic valve both hemodynamically and pathologically. Goto's comments on this matter are also quoted in other articles, as follows 2,3: The point of Dr. Shemin's article was the evaluation of a unileaflet pericardial bioprosthetic valve both hemodynamically and pathologically in sheep and was not for evaluation of calcification in the dog. Dr. Shemin considered that the dog was not a useful model for calcification according to previous investigations 2,3 that demonstrated no significant calcification despite 2 years of valve function in dogs.
We used dogs to evaluate our new conduit hemodynamically and pathologically. The aim of our study was not the evaluation of calcification. If Dr. Goto is interested in the anticalcification effect of our bioprosthesis, we suggest he may want to study our conduit in sheep. The details of the graft processing are noted in "Materials and methods" and "Discussion" of our article. References 4,5 are added for additional clarification.
Dr. Goto explained the calcification of the polyepoxy compound–treated aorta based on his colleague's personal data. However, since this is not published information, we would need more information to respond more specifically. The laboratory data, including the number of animals, name and concentration of the polyepoxy compound, and the catalyst, reaction velocity, reaction time, temperature, change of the pH during cross-linking, collagen content of the aortic wall, cross-linking ratio of the collagen, and the pK of the material in wet condition would be necessary before we could comment.
First Department of SurgeryYokohama City University School of Medicine3-9 Fukuura, Kanazawa-ku,
Yokohama 236, Japan12/8/87681
References
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Shemin RJ, Schoen FJ, Hein R, Austin J, Cohn LH. Hemodynamic and pathologic evaluation of a unileaflet pericardial bioprosthetic valve. J Thorac Cardiovasc Surg 1988;95:912-9
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Gabbay S, Frater RWM. The unileaflet heart valve bioprosthesis: new concept. In: Cohn LH, Gallucci V, editors. Cardiac bioprostheses. New York: Yorke Medical Books; 1982. p. 411-24.
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Gabbay S, Frater RWM. The Meadox uni-cusp heart valve bioprosthesis. Information Cardiol 1983(July-August):651-7.
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Noishiki Y, Miyata T. A method to heparinize the collagen materials. Fourth Meeting of the Japanese Society of Biomaterials, Tokyo, November 1982.
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Miyata T, Noishiki Y, Matsumae M, Yamane Y. A new method to give an antithrombogenicity to biological materials and its successful application to vascular grafts. ASAIO Trans 1983;29:363.
